Clinical value of extravascular lung water combined with central venous-to-arterial carbon dioxide difference/arterial-to-venous oxygen difference ratio in early treatment of patients with septic shock

Abstract:

Objective：To investigate the clinical value of extravascular lung water（EVLW） combined with central venous-arterial par－tial pressure of carbon dioxide/arterial-central venous oxygen content difference ratio[P（cv-a）CO2/C（a-cv）O2 ] in the early treatment of septic shock. Methods：A total of 50 patients with septic shock who were admitted to the intensive care unit（ICU） of The Second Affiliated Hospital of Chongqing Medical University and Chongqing Hospital of Traditional Chinese Medicine from 2015 to 2017 were enrolled and randomly divided into early goal-directed therapy（EGDT） group with 28 patients and EVLW+P（cv-a）CO2/C（a-cv）O2 group with 22 patients（P/C group）. Mean arterial pressure（MAP），heart rate（HR），and central venous pressure（CVP） were con－tinuously monitored for all patients，and arterial blood samples and central venous blood samples were collected for blood gas analysis to measure PaCO2，PcvCO2，PcvO2，ScvO2，Hbcv，PaO2，SaO2，Hba，and blood lactate at the time of ICU admission and at 6 hours after resuscitation. P（cv-a）CO2/C（a-cv）O2 was calculated；CaO2=1.34×Hba×SaO2+0.003×PaO2，CcvO2=1.34×Hbcv× ScvO2+0.003×PcvO2，and C（a-cv）O2=CaO2-CcvO2. For patients in the P/C group，extravascular lung water（EVLW） was measured by pulse-induced contour cardiac output（PiCCO），once every 3 hours，and the mean value of three consecutive measurements was recorded. Lactate clearance rate was calculated according to the following equation：lactate clearance rate=（blood lactate value at the time of ICU admission-blood lactate value at 6 hours after resuscitation）/blood lactate value at the time of ICU admission×100%. The dose of the vasoactive agent norepinephrine within 6 hours after resuscitation was compared between the two groups. The 28-day mortality rate was calculated. Related indices after fluid resuscitation were compared between the two groups. Results：There were no significant differences between the two groups in MAP，ScvO2，and the proportion of patients achieving EGDT target at 6 hours after fluid resus－citation（P>0.05）. Compared with the EGDT group，the P/C group had significantly higher lactate clearance rate at 6 hours after fluid resuscitation and urine volume per hour（P<0.05），as well as significantly lower resuscitation fluid volume，CVP，P（cv-a）CO2/C（a-cv）O2，and dose of vasoactive agent（P<0.05）. There was no significant difference in 28-day mortality rate between the two groups（P>0.05）. Conclusion：EVLW combined with P（cv-a）CO2/C（a-cv）O2 can be used to guide EGDT for septic shock. It can accurately evaluate tissue perfusion and volume load in patients with septic shock as early as possible and guide the rational use of liquid therapy and vasoactive drugs in clinical practice.